fix: Correct compilation errors in PhotoReasoningViewModel

This commit addresses compilation errors that arose from the implementation of the stop button functionality.

- Corrected unresolved `isActive` references by explicitly using `coroutineContext.isActive` within coroutines and suspend functions. This ensures checks are made against the correct coroutine context.
- Reviewed `return` statements within `sendMessageWithRetry` and related functions to ensure they correctly exit from the intended scope.

These changes resolve the build failures and ensure the stop functionality operates as intended with proper coroutine cancellation checks.

Author: google-labs-jules[bot]

app/src/main/kotlin/com/google/ai/sample/feature/multimodal/PhotoReasoningViewModel.kt

@@ -132,16 +132,16 @@ class PhotoReasoningViewModel(
         currentReasoningJob = PhotoReasoningApplication.applicationScope.launch(Dispatchers.IO) {
             // Create content with the current images and prompt
             val inputContent = content {
-                if (!isActive) return@launch // Check for cancellation
+                if (!coroutineContext.isActive) return@launch // Check for cancellation
                 for (bitmap in selectedImages) {
-                    if (!isActive) return@launch // Check for cancellation
+                    if (!coroutineContext.isActive) return@launch // Check for cancellation
                     image(bitmap)
                 }
-                if (!isActive) return@launch // Check for cancellation
+                if (!coroutineContext.isActive) return@launch // Check for cancellation
                 text(prompt)
             }
 
-            if (!isActive) return@launch // Check for cancellation
+            if (!coroutineContext.isActive) return@launch // Check for cancellation
             sendMessageWithRetry(inputContent, 0)
         }
     }
@@ -192,15 +192,15 @@ class PhotoReasoningViewModel(
      * @param retryCount The current retry count
      */
     private suspend fun sendMessageWithRetry(inputContent: Content, retryCount: Int) {
-        if (!isActive || stopExecutionFlag.get()) { // Check for cancellation
+        if (!coroutineContext.isActive || stopExecutionFlag.get()) { // Check for cancellation
             _uiState.value = PhotoReasoningUiState.Success("Operation cancelled before sending.")
             updateAiMessage("Operation cancelled.")
             return
         }
         try {
             // Send the message to the chat to maintain context
             val response = chat.sendMessage(inputContent)
-            if (!isActive || stopExecutionFlag.get()) { // Check for cancellation
+            if (!coroutineContext.isActive || stopExecutionFlag.get()) { // Check for cancellation
                 _uiState.value = PhotoReasoningUiState.Success("Operation cancelled after sending.")
                 updateAiMessage("Operation cancelled.")
                 return
@@ -212,13 +212,13 @@ class PhotoReasoningViewModel(
             response.text?.let { modelResponse ->
                 outputContent = modelResponse
 
-                if (!isActive || stopExecutionFlag.get()) { // Check for cancellation
+                if (!coroutineContext.isActive || stopExecutionFlag.get()) { // Check for cancellation
                      _uiState.value = PhotoReasoningUiState.Success("Operation cancelled during response processing.")
                     updateAiMessage("Operation cancelled.")
                     return
                 }
                 withContext(Dispatchers.Main) {
-                     if (!isActive || stopExecutionFlag.get()) { // Check for cancellation
+                     if (!coroutineContext.isActive || stopExecutionFlag.get()) { // Check for cancellation
                         _uiState.value = PhotoReasoningUiState.Success("Operation cancelled.")
                         updateAiMessage("Operation cancelled.")
                         return@withContext
@@ -234,13 +234,13 @@ class PhotoReasoningViewModel(
             }
 
             // Save chat history after successful response
-            if (isActive && !stopExecutionFlag.get()) {
+            if (coroutineContext.isActive && !stopExecutionFlag.get()) {
                 withContext(Dispatchers.Main) {
                     saveChatHistory(MainActivity.getInstance()?.applicationContext)
                 }
             }
         } catch (e: Exception) {
-            if (!isActive || stopExecutionFlag.get()) { // Check for cancellation during exception handling
+            if (!coroutineContext.isActive || stopExecutionFlag.get()) { // Check for cancellation during exception handling
                 _uiState.value = PhotoReasoningUiState.Error("Operation cancelled during error handling.")
                 updateAiMessage("Operation cancelled during error handling.")
                 return
@@ -249,22 +249,22 @@ class PhotoReasoningViewModel(
 
             // Check specifically for quota exceeded errors first
             if (isQuotaExceededError(e) && apiKeyManager != null) {
-                if (!isActive || stopExecutionFlag.get()) return // Check for cancellation
+                if (!coroutineContext.isActive || stopExecutionFlag.get()) return // Check for cancellation
                 handleQuotaExceededError(e, inputContent, retryCount)
                 return
             }
 
             // Check for other 503 errors
             if (is503Error(e) && apiKeyManager != null) {
-                if (!isActive || stopExecutionFlag.get()) return // Check for cancellation
+                if (!coroutineContext.isActive || stopExecutionFlag.get()) return // Check for cancellation
                 handle503Error(e, inputContent, retryCount)
                 return
             }
 
             // If we get here, it's not a 503 error or quota exceeded error
-            if (isActive && !stopExecutionFlag.get()) {
+            if (coroutineContext.isActive && !stopExecutionFlag.get()) {
                 withContext(Dispatchers.Main) {
-                     if (!isActive || stopExecutionFlag.get()) return@withContext// Check for cancellation
+                     if (!coroutineContext.isActive || stopExecutionFlag.get()) return@withContext// Check for cancellation
                     _uiState.value = PhotoReasoningUiState.Error(e.localizedMessage ?: "Unknown error")
                     _commandExecutionStatus.value = "Error during generation: ${e.localizedMessage}"
 
@@ -335,7 +335,7 @@ class PhotoReasoningViewModel(
      * Handle quota exceeded errors specifically
      */
     private suspend fun handleQuotaExceededError(e: Exception, inputContent: Content, retryCount: Int) {
-        if (!isActive || stopExecutionFlag.get()) return // Check for cancellation
+        if (!coroutineContext.isActive || stopExecutionFlag.get()) return // Check for cancellation
         // Mark the current API key as failed
         val currentKey = MainActivity.getInstance()?.getCurrentApiKey()
         if (currentKey != null && apiKeyManager != null) {
@@ -412,7 +412,7 @@ class PhotoReasoningViewModel(
                     )
 
                     // Retry the request with the new API key
-                    if (!isActive || stopExecutionFlag.get()) return // Check for cancellation
+                    if (!coroutineContext.isActive || stopExecutionFlag.get()) return // Check for cancellation
                     sendMessageWithRetry(inputContent, retryCount + 1)
                     return
                 }
@@ -424,7 +424,7 @@ class PhotoReasoningViewModel(
      * Handle 503 errors (excluding quota exceeded errors)
      */
     private suspend fun handle503Error(e: Exception, inputContent: Content, retryCount: Int) {
-        if (!isActive || stopExecutionFlag.get()) return // Check for cancellation
+        if (!coroutineContext.isActive || stopExecutionFlag.get()) return // Check for cancellation
         // Mark the current API key as failed
         val currentKey = MainActivity.getInstance()?.getCurrentApiKey()
         if (currentKey != null && apiKeyManager != null) {
@@ -498,7 +498,7 @@ class PhotoReasoningViewModel(
                     )
 
                     // Retry the request with the new API key
-                    if (!isActive || stopExecutionFlag.get()) return // Check for cancellation
+                    if (!coroutineContext.isActive || stopExecutionFlag.get()) return // Check for cancellation
                     sendMessageWithRetry(inputContent, retryCount + 1)
                     return
                 }
@@ -589,13 +589,13 @@ class PhotoReasoningViewModel(
     private fun processCommands(text: String) {
         commandProcessingJob?.cancel() // Cancel any previous command processing
         commandProcessingJob = PhotoReasoningApplication.applicationScope.launch(Dispatchers.Main) {
-            if (!isActive || stopExecutionFlag.get()) return@launch // Check for cancellation
+            if (!coroutineContext.isActive || stopExecutionFlag.get()) return@launch // Check for cancellation
             try {
                 // Parse commands from the text
                 val commands = CommandParser.parseCommands(text)
 
                 if (commands.isNotEmpty()) {
-                    if (!isActive || stopExecutionFlag.get()) return@launch
+                    if (!coroutineContext.isActive || stopExecutionFlag.get()) return@launch
                     Log.d(TAG, "Found ${commands.size} commands in response")
 
                     // Update the detected commands
@@ -611,7 +611,7 @@ class PhotoReasoningViewModel(
 
                     // Execute the commands
                     for (command in commands) {
-                        if (!isActive || stopExecutionFlag.get()) { // Check for cancellation before executing each command
+                        if (!coroutineContext.isActive || stopExecutionFlag.get()) { // Check for cancellation before executing each command
                             Log.d(TAG, "Command execution stopped before executing: $command")
                             _commandExecutionStatus.value = "Command execution stopped."
                             break // Exit loop if cancelled
@@ -626,7 +626,7 @@ class PhotoReasoningViewModel(
                                 break
                             }
                         } catch (e: Exception) {
-                            if (!isActive || stopExecutionFlag.get()) break // Exit loop if cancelled during error handling
+                            if (!coroutineContext.isActive || stopExecutionFlag.get()) break // Exit loop if cancelled during error handling
                             Log.e(TAG, "Error executing command: ${e.message}", e)
                             _commandExecutionStatus.value = "Error during command execution: ${e.message}"
                         }
@@ -636,7 +636,7 @@ class PhotoReasoningViewModel(
                     }
                 }
             } catch (e: Exception) {
-                 if (!isActive || stopExecutionFlag.get()) return@launch
+                 if (!coroutineContext.isActive || stopExecutionFlag.get()) return@launch
                 Log.e(TAG, "Error processing commands: ${e.message}", e)
                 _commandExecutionStatus.value = "Error during command processing: ${e.message}"
             } finally {